Visual stimulus placement comparison for Turkish P300 speller

A P300 speller is designed, that is implemented with Turkish characters. The designed P300 speller is used as a brain computer interface via electroencephalogram (EEG). For this speller, the visual stimulus has been prepared for two different letter placements. The first of these placements, which is very common in the literature, is the square formed letter sequence. The second placement of letters is designed to consist of a gap on top and at the bottom rows of letters in the form of parallelogram. For the two different letter placements, data are collected from the subjects. The data are evaluated for the placement changes´ effects on the designed P300 speller.